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Subaru Forester Tire/Wheel Questions

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  • My friend has the R/T 's but I went with the Altimax HP 's based on the tirerack ratings. I initially had the same concern about tread design but so far these tires have been great. I have yet to drive them in the snow myself so I can't personally tell you. They handle great and stick to the road when raining so I have no regrets as to my choice so far. I feel confident that I won't have any problems come winter time. I extensively researched tires for my Forester and I think General tires have finally got a great line at very good prices. I hope this helps, good luck.
  • occkingoccking Posts: 346
    Ok, guys looking for feedback on this matter

    Tuesday I stopped into Mastrial Subaru, after returning from a long trip for regular oil change (21,500 miles) When I left, within 1/2 mile the tire pressure monitor started to blink, then remain on steadily lit.

    That evening went to a gas station & found out tire pressures were normal (32 psi I believe for front and 30 psi for rear) As I am leaving on another long trip tomorrow and didn't want to have to look at the irritating light I called the dealer & they said come on in, probably have to reset something.

    Well, that's what I did this morning. Want to hear the explanation?? They claim that one of the tires was filled with 72 psi! They have no explanation how that much air got in the tire. Again, when I went there on Tuesday, everything seemed to be normal, right after I left the problem arose.

    No explanation how that could have happened. But something happened while I was at the dealer. I certainly did not go to a gas station right after leaving there & put that much air in. I would be scared to to hell to stand next to a tire and put that much air in. Dealer claims no one at their place would have done such a dastardly deed (either on purpose or by accident) I know that outside temperature fluctiations can cause a small jump up or down, but nothing like increasing it by more than 50%.

    The more and more I think about it, something had to have happened at the dealer, and unlikely an accident. Had I gone on my next long trip (from Providence, RI to Buffalo, NY tomorrow) and driven all those miles on a tire inflated so high, could anything have happened? This really perturbs me.

    I have a great relationship with the service dept at this dealer, and don't want to make false accusations, but they insisted one tire was over 72 psi, and that caused the light to go off.

    Any comments????
  • ateixeiraateixeira Posts: 72,587
    I think an inaccurate reading is far more likely.

    Heat will increase pressure, but if it made it all the way up to 72psi the tire likely would have suffered severe damage or wear.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    If you checked the pressure, and it was normal in all four tires, I cannot imagine that something like a tire inflated with double pressure would have occurred. I would say a faulty TPM sensor would be a more likely culprit. Any time one of those stops working or is not present, the result is the exact sequence you described: The light blinks for a while shortly after starting the car (probably 30 to 60 seconds later), then remains steadily lit. I have a set of wheels on my '10 Forester with no TMP sensors in them, and this is the result. I am not sure if it behaves the same way when a sensor is reading a condition "out of range," meaning the pressure is either too low or too high.

    However, in the event the tire was overinflated so severely, the result depends on several factors: 1. The tire's integrity (number of miles, condition of materials, etc), 2. The road surface, 3. the vehicle's load, and 4. the ambient and road surface temperatures. Basically.... heat + pressure = boom.

    This time of year (cooler temps), of more concern may be the amount of vibration being transferred to the struts and wheel assemblies. Over extended periods, that could result in premature wear of parts.
  • ateixeiraateixeira Posts: 72,587
    heat + pressure = boom

    I love it when we get all scientific! :D
  • occkingoccking Posts: 346
    I agree with you 100%! It is the dealer who insisted there was 72 psi in one tire. I certainly did put that much in. The problem occured between the time I left the car for service on that afternoon and 1/2 mile after I left is when the light went on.

    Could a tire even hold that much psi without blowing? You are probably right the dealer read it wrong. But, you would think, from a dealer, they would be intelligent enough to know whether that is even possible.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    Yes, a tire can hold that much pressure. I know from experience.... ;) :blush:
  • msage1msage1 Posts: 1
    I have a Forester. Does it matter where I have my tires rotated? Is there anything I need to be aware of with the AWD?
  • ateixeiraateixeira Posts: 72,587
    Rotate 'em every 7500 miles or so to keep wear even on all 4 tires. You want to keep the circumference of all the tires right about the same. :shades:
  • emememem Posts: 3
    I need 4 tires for my 04 Forester xs;could use some recommendations
    p21560r16 AWD, 25k a year Boston area and need to be mobile in the snow

    I got a real good price on 4 Falcon tires??

    thanks
  • emememem Posts: 3
    ( wrong spelling) Falken
  • I have a 2006 Forester and last checked my air pressure in mid September. I usually do it every other week but I fractured my ankle in early October and have not been able to drive since and my wife has become my chauffer. Checked my air pressure yesterday and all 4 tires were at approx 15 lbs. My mazda, also with alloy wheels, is fine. I understand that sometimes air can leak around alloy wheels. OK. But is there any solution other than checking the pressure weekly?
  • laredo13laredo13 Posts: 6
    edited December 2010
    If you constantly drive on snowy roads do yourself a favor and buy a set of dedicated winter/snow tires. Buying dedicated snows will cost you more money now, but the money, aggravation and injuries you may save in the long run will be well worth the initial investment. If based on your driving conditions you choose all season tires than you won't be disappointed with the General Altimax HP. Falken tires are garbage. My father always told me that their are two things that are most important when it comes to a car. NEVER skimp on tires and brakes as your life may depend on it. Go to tirerack.com and do your research. Good luck and drive safe.
  • ateixeiraateixeira Posts: 72,587
    Keep in mind the temperature drop may be largely responsible for the drop in tire pressure in this case. You need to check more often when the temps dip significantly.

    When it warms up, too, to let air out, else you may up with 40psi in summer!
  • ateixeiraateixeira Posts: 72,587
    edited December 2010
    Falken Ziex 512s are fine, the one bad thing about them is tread life, but that doesn't make it a bad tire overall. Grip is actually far above average.

    I actually owned 3 sets of them - on an 03 Miata, 98 Forester, and 02 Legacy. Not a great winter tire, but good grip even in the wet otherwise.

    Again, my only complaint is short tread life.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    In terms of tread life and all-season capability, I very much like the Goodyear Assurance TripleTread. I had a set on my 1996 Outback, and they were fantastic. Unfortunately, I was only able to use them for 13 months and about 25,000 miles before we (me and the car) parted ways, but I used them over two winters and they were great. They also only wore ~2/32 during that time.

    They will last you about three years with your driving habits and they'll give you very decent traction on snow and ice.
  • I'm a Chicago woman who has a 2008 forester 2.5X (so my manual says) who is not an expert in cars. Apparently I haven't rotated my tires often enough and the sides of the two front tires are bald. My car just hit 28,000. The dealer wants me to buy two new Yokahama tires for the front, get an alignment and then rotate the backs to the front. We have had a horrendous winter with snow and ice. The Yokahamas never worked well in rain, and are nightmares in winter; I'm slipping and sliding. I've seen at least 10 suggested tires for the last 5 years of this blog. What do you recommend-are there any good ones out there? i need to get something ordered ASAP because my 2 and a half year old Suburu is a scary car to drive. I don't feel safe in it right now. By the way, what are suburbucks?
    Thanks....
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    First, of all, I would run quick from that dealer! You definitely should not purchase only two tires to replace the worn ones. If you do that, you will put heavy stress on the center differential and may very well end up with much more serious problems (such as a center differential failure!) down the road.

    I agree that your tires, the Yokohama Geolandar, are horrendous (for winter conditions).

    Are you wanting to purchase an all-season tire that performs decently during winter, or have you considered running two sets - one for winter and one for summer? If you go with the two-set approach, you can probably run your Geolandars for another summer to help spread out the extra initial tire investment.

    The best all-season tire I have used is the Goodyear Assurance TripleTred. It has an excellent treadwear life as well. Tirerack.com is a good place to go to get an idea of how you can expect a tire to perform. They have a (subjective) rating system based on user feedback, so you can compare tires within a given class and read reviews.
  • capriracercapriracer Somewhere in the USPosts: 795
    Second vote for RUNNIG from that dealer. Read your owners manual. It ought to say somewhere in there that you have to be careful about tire diameter - and that means tires have to be replaced in sets of 4.

    And the cause of the eneven wear is alignment. Get that fixed, too!
  • laredo13laredo13 Posts: 6
    edited January 2011
    With 28,000 miles on your set of Yokohama's I'd replace all four. Stay away from dealers and find a reputable mechanic for this type of repair. Bridgestone 960 or General Altima HP would be a great choice for an all season tire. The General is just as good at a much lower price. I love them. As I've said before, don't skimp on tires and brakes. These are two of the most important items where money should not override safety. Yes, it would also be a good idea to check alignment at this time. Good Luck...
  • danielldaniell Posts: 128
    edited January 2011
    I have a 2002 Forester S, automatic, with limited slip differential. I have religiously rotated my tires to keep their circumferences matched.

    I agree that in theory at least all 4 tires should be changed at the same time. The manual says: "For safe vehicle operation SUBARU recommends replacing all four tires at the same time". There is a warning after that that mixing tires can produce damage to the drivetrain.

    However, even the flat tire change procedure described does not specify that the spare (I have full size spare on my 2002) needs to go to he back, nor are there any mileage or speed limitations stated in the manual. There is no requirement (as i have seen in many posts) to put the vehicle in FWD mode. Basically the manual describes the flat tire replacement as it would be for a FWD or RWD car. If a different spare tire circumference could cause problems, why isn't it stated in the manual?

    I am wondering if the manual transmission Subarus (50-50 traction F/R) have the more stringent requirements, while the autos do not.

    Daniel
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    The automatics are definitely sensitive to differences. The speed limitation of using a "donut" tire is from the tire itself, not due to the stress it places on the drivetrain. If you have one tire that is of a different circumference, the stress will be on that axle's differential. If you have both tires on one axle different in circumference from the other axle, the stress then goes to the center differential.

    I can't imagine anyone driving on a donut for an extended period of time, but were that to happen, it could damage the differential because of the added stress, especially if the vehicle is driven on paved roads. On snow, ice, and gravel, the stress is more often relieved through tire slippage.
  • danielldaniell Posts: 128
    Edited my previous post a bit to include specifically some info from the manual...

    I agree with everything you say, theoretically. All I am saying is that the manual does not seem to put any serious restrictions on the tire circumference. If so, it would require installing the spare in the back, putting the car in FWD mode etc. as described in other posts. The only cautionary words about tire replacement are: "Have the wheel nut torque checked at the nearest automotive sevice facility. Store the flat tire in the spare tire compartment". If circumference was such a big concern, they would have said something like "repair your flat tire at the closest facility if possible, and install it back". No such words, they allow you to use the spare permanently.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    edited January 2011
    It seems as though they have become more detailed in the owner's manual in recent years. In the 2010 manual, beginning on page 9-2, it states:

    CAUTION: Never use any temporary spare tire other than the original. Using other sizes may result in severe mechanical damage to the drive train of your vehicle.

    The temporary spare tire is smaller and lighter than a conventional tire and is designed for emergency use only. Remove the temporary spare tire and reinstall the conventional tire as soon as possible because the spare tire is designed only for temporary use. Check the inflation pressure of the temporary spare tire periodically to keep the tire ready for use. The correct pressure is 60 psi (420 kPa, 4.2 kg/cm2).

    When using the temporary spare tire, note the following.
    . Do not exceed 50 mph (80 km/h).
    . Do not put a tire chain on the temporary spare tire. Because of the smaller tire size, a tire chain will not fit properly.
    . Do not use two or more temporary spare tires at the same time.
    . Do not drive over obstacles. This tire has a smaller diameter, so road clearance is reduced.
    . When the wear indicator appears on the tread, replace the tire.
    . The temporary spare tire must be used only on a rear wheel. If a front wheel tire gets punctured, replace the wheel with a rear wheel and install the temporary spare tire in place of the removed rear wheel.

    Precautions for AWD models with automatic transmission:
    Your vehicle is equipped with the AWD (All-Wheel Drive) system. In addition, if your vehicle is an AT model, before driving your vehicle with the temporary spare tire, deactivate the AWD capability of the vehicle as follows.
    1. Turn the ignition switch to the “LOCK” position.
    2. Pull any one spare fuse out of the spare fuse holder in the engine compartment. Spare fuses are attached on the back side of the fuse holder cover. You may pick up any one fuse in the spare fuse holder.
    3. Put a spare fuse inside the FWD connector located in the cabin and confirm that the All-Wheel Drive warning light “ ” illuminates. The All-Wheel-Drive capability of the vehicle has now been deactivated.

    NOTE: After reinstalling the conventional tire, remove the spare fuse from the FWD connector in order to reactivate All-Wheel Drive. Make sure to restore the removed spare fuse in the spare fuse holder located in the engine compartment.
  • danielldaniell Posts: 128
    Thank you for the detailed answer.

    It seems that most if not all of those additional precautions are caused by the doughnut spare tire being vastly different from the remaining 3 tires. My car came with the full size spare from the factory, and again, I see none of these additional steps in the manual. Based on that, it seems that the AWD can accomodate fairly different circumferences. Another pointer in that direction - the "light load" tire pressure recommended in the back is 28 psi, "heavy load" is 36 psi, and always 29 psi in the front (numbers from memory, but I believe I am right - wife has the car now). Big difference between 29 psi and 36 psi. Bottom line, acording to my 2002 manual at least, restrictions when replacing with same size tire as my spare is seem to be rather related to driving dynamics and traction characteristics than circumference.

    Based on all of this, IMO it does not seem completely unreasonable that replacing just 2 tires as opposed to all 4 is possible.

    Daniel
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    Well, it is possible, but it will place additional stress on the center differential. If left in that state long enough, the differential is likely to fail. The driver might not even notice it happen, but that one time AWD is really needed, the front tires are going to be spinning and the rear will be doing nothing to help.

    If you have a full-size spare, there is much less of a difference in circumference and therefore much less stress on the system. If you keep the spare rotated in with the other tires, you could even drive on it regularly with no problems. But, if you only use it as the spare, you should swap it back off the car as soon as is reasonable.

    You're right - most of the precautions in the 2010 manual are specific to the donut spare. There would be no location or speed restrictions on a full-size. I did not realize that the 2002 model included a full-size from the factory. The 2009+ models can accommodate a full-size in the well, but come with a donut.
  • danielldaniell Posts: 128
    edited January 2011
    One can put 2 new tires on the same side of the car, or opposite diagonally. That would move the mismatch from the center differential to the front and rear differentials. Lots of people with FWD and RWD cars change just one tire and differential failures as a problem are generally rare.

    Here is a very relevant article I found. It's not about Subaru or AWD, but shows real, measured impact of tire pressure. The author found that while the impact of tire pressure on circumference is very small, "The “roll-out” of the rear tires was reduced by 1” by simply reducing the tire pressures from 25 psi to 14 psi." Basically the same tire with 25 psi covered an extra inch on the ground with each rotation, compared to when inflated to 14 psi. One inch per rotation is huge, and that's just the impact of tire pressure. Below is the link. The guy even shows pictures of his measurements.

    http://www.onedirt.com/tech-stories/tire-pressure-101-the-cushion-of-air/

    Again, the range for the rear tire pressure recommended by Subaru is 28 psi to 36 psi based on load, quite big itself. Based on all of this, I will have no problem replacing just one tire (and perhaps fine tune the roll-out using the tire pressure) if needed.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,461
    edited January 2011
    There are a lot of assumptions there!

    First, yes, you could put a new tire on each axle and take pressure off the center differential and transfer it to the other two differentials. I did replace a single tire as I didn't realize it would cause a problem; that was about 20,000 miles into a set of tires that were on the car for 75,000 miles. When on dry roads, I didn't even notice the difference. On slick roads, the axle with that tire would slip every 3-4 seconds and create a noticeable "wobble" in the movement of the car. At about 185,000 miles (on the odometer - I put a new set of tires on at around 196,000), I started to get some differential noise from the rear diffy that became more consistent over time, but it still operated fine on my open-differential '96 Outback through 220,000 miles when I ceased to own it.

    Second, you are making the assumption with tire pressure that the contact patch and sidewall height change in a linear fashion with tire pressure, which is not the case. The difference between 14 and 25 psi is worlds different from 28 to 36 psi. If you operated the car at the former difference for any length of time, it would create problems. At the latter, it would not. However, were one to drive the car at, say, an even 28 psi all around but carry a heavy load in the back at all times, it may cause additional stress on the drive line.

    In the end, it really all depends on your priorities. If you want a well-functioning and maintained car, it doesn't pay to scrimp or neglect. If you don't care and can pass it on to some unsuspecting victim before any problems become easily apparent, scrimp away.
  • danielldaniell Posts: 128
    edited January 2011
    Not to worry, I completely realized the difference between 14-25 psi and 28-36 psi, and the likely non-linearity :) I am a mathematician, and I deal with stuff like that a lot in my job. Just did not want to go there. But I'd be willing to bet that the 28-36 increase in psi with a full load will cause more than the 1/4" Subaru demands.

    What bugged and still bugs me is that there is little information available about this issue. My suspicion is that the Subaru AWD can deal with more than the 1/4" circumference difference required, easily. Your own story proves that the Subaru AWD system can take a lot. I can only dream to reach that kind of mileage with my car (too many problems, in spite of being extremely well maintained). And simply we don't drive enough (reaching 90k miles in 9.5 years of ownership).

    I suspect a lot of requirements in the manual are due to the litigious world we live in. For example, the manual specifies front to back rotation on each side. I got non-directional tires from Sears, with lifetime rotation and balance, but they refuse to do a FWD-pattern or X-rotation, because of the specs in the manual. So I go to Sears, have my tires balanced, then go home and do a proper FWD rotation. That doesn't make sense. I assume the only reason that is in the manual is because some OEM tires they use are directional. Just for the record, I am doing the FWD rotation pattern rather than X (cross) rotation because my auto Forester has 90% forward bias. So far that has worked very well.
  • paisanpaisan Posts: 21,181
    Having worked on Subarus for 10+ years, raced them for 10+ years and owned them for more than 12 years. I can tell you that you DO NOT want to drive a Subaru with a tire that is mis-matched for any extended period of time. You can drive it for say 200 or 300 miles but to drive it 30,000 or 40,000 miles WILL definitely cause your center diffy to fail eventually over time. If your subaru is equipped with a front or rear Limited Slip Differential, you should also put the mismatched tire on the axle w/o the LSD.

    -mike
    Subaru Guru and Track Instructor
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